1. Field of the Invention
The invention relates to an erosion apparatus for the shaping machining of a metallic structural component or insert element as well as a method for the eroding of such elements or components with an erosion apparatus. This machining can include the machining of a metallic structural component or can include the machining of a metallic insert element in a non-metallic structural component or the machining of a metallic insert element placed in an insulated manner in a metallic structural component. In the two latter alternatives, the removal of metallic connecting elements from structural components is concerned in particular.
2. Discussion of Background Information
Erosion processes are known from the general prior art with which structural components are machined in a shaping manner by way of an electrode. In these methods, the material in the vicinity of the erosion processes is impaired. For this reason prior methods are not usable on components or structural components whose material properties can be changed in an inadmissible manner by the erosion process.
To remove connecting elements from structural components, tap drills were previously used that cut the connecting element to be removed, e.g., the rivet, centrally. A disadvantage of this drilling process is that structural parts that are held together by the connecting elements may be damaged. This is particularly the case when rivets are to be removed, since they must be bored out up to the transition point lying between the rivet head and the rivet neck, and at this point, the structural parts connected with the rivet are adjacent each other.
In aircraft construction, in particular, connection rivets with high-tensile drawing mandrels are used at points that are accessible only on one side. Thus a very hard material is present precisely in the center of the rivet, so that when connecting elements are removed according to the prior art, the following further problems result: the quality of the centering, i.e., the precision with which the power drill is applied, depends on the manual dexterity of the craftsman, resulting however in a scatter with relatively imprecise centerings. Moreover, the tool, i.e., the drill, wears particularly severely at draw rivets as a function of the pressing pressure exerted. Another disadvantage is a possible heat development that occurs, in particular, when the cutting action of the drill decreases sharply due to wear, or the rivet turns together with the tool, which causes increased frictional heat and through which damage to the structure (structural change) can occur.
For these reasons this drilling process is only suitable to a limited extent for the removing of connection rivets with drawing mandrels.